Details
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Bug
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Status: Closed (View Workflow)
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Minor
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Resolution: Fixed
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1.1.0
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None
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None
Description
I think it's a minor issue because JDBC does not explicitly state that Connection.close() must close a statement and result sets; but in the current state it's particularly error-prone, and hanging isn't good, so if it's possible, it would be good to fix. MySQL Connector/J doesn't show this problem.
The following test case sets a non-zero fetch size for a statement and then executes a query with a sizable enough result set. Before all values are fetched, the connection gets closed, but the operation never ends.
Test case:
import java.sql.DriverManager; |
import java.sql.Connection; |
import java.sql.Statement; |
import java.sql.ResultSet; |
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public class NonFinishedFetch |
{
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public static void main (String argv[]) throws Exception |
{
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try { |
String dsn = "jdbc:mysql://localhost:3306/test?user=root"; |
Statement stmt = null; |
ResultSet rs = null; |
Connection conn = DriverManager.getConnection(dsn);
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stmt = conn.createStatement();
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stmt.execute("DROP TABLE IF EXISTS t1"); |
stmt.execute("CREATE TABLE t1 (a VARCHAR(1024))"); |
String st = "INSERT INTO t1 VALUES (REPEAT('a',1024))"; |
for ( int i=1; i<=100; i++) { |
st = st + ",(REPEAT('a',1024))"; |
}
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stmt.setFetchSize(Integer.MIN_VALUE);
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stmt.execute(st);
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rs = stmt.executeQuery("SELECT * FROM t1 a, t1 b"); |
conn.close();
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} catch (Exception e) { |
e.printStackTrace();
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}
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}
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}
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Stack trace:
Full thread dump OpenJDK 64-Bit Server VM (20.0-b12 mixed mode):
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"Attach Listener" daemon prio=10 tid=0x0000000001afe000 nid=0x2089 runnable [0x0000000000000000]
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java.lang.Thread.State: RUNNABLE
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Locked ownable synchronizers:
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- None
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"Low Memory Detector" daemon prio=10 tid=0x0000000001a0b800 nid=0x2079 runnable [0x0000000000000000]
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java.lang.Thread.State: RUNNABLE
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Locked ownable synchronizers:
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- None
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"C2 CompilerThread1" daemon prio=10 tid=0x0000000001a06800 nid=0x2078 waiting on condition [0x0000000000000000]
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java.lang.Thread.State: RUNNABLE
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Locked ownable synchronizers:
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- None
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"C2 CompilerThread0" daemon prio=10 tid=0x0000000001a03800 nid=0x2077 waiting on condition [0x0000000000000000]
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java.lang.Thread.State: RUNNABLE
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Locked ownable synchronizers:
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- None
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"Signal Dispatcher" daemon prio=10 tid=0x0000000001a02800 nid=0x2076 runnable [0x0000000000000000]
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java.lang.Thread.State: RUNNABLE
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Locked ownable synchronizers:
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- None
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"Finalizer" daemon prio=10 tid=0x00000000019e3800 nid=0x2075 in Object.wait() [0x00007f8985d2f000]
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java.lang.Thread.State: WAITING (on object monitor)
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at java.lang.Object.wait(Native Method)
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- waiting on <0x00000000ec7782c0> (a java.lang.ref.ReferenceQueue$Lock)
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at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:133)
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- locked <0x00000000ec7782c0> (a java.lang.ref.ReferenceQueue$Lock)
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at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:149)
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at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:177)
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Locked ownable synchronizers:
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- None
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"Reference Handler" daemon prio=10 tid=0x00000000019dc000 nid=0x2074 in Object.wait() [0x00007f8985e30000]
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java.lang.Thread.State: WAITING (on object monitor)
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at java.lang.Object.wait(Native Method)
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- waiting on <0x00000000ec778360> (a java.lang.ref.Reference$Lock)
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at java.lang.Object.wait(Object.java:502)
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at java.lang.ref.Reference$ReferenceHandler.run(Reference.java:133)
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- locked <0x00000000ec778360> (a java.lang.ref.Reference$Lock)
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Locked ownable synchronizers:
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- None
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"main" prio=10 tid=0x0000000001971800 nid=0x2070 runnable [0x00007f898cbd8000]
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java.lang.Thread.State: RUNNABLE
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at java.net.SocketInputStream.socketRead0(Native Method)
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at java.net.SocketInputStream.read(SocketInputStream.java:146)
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at java.net.SocketInputStream.read(SocketInputStream.java:199)
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at org.mariadb.jdbc.internal.mysql.MySQLProtocol.close(MySQLProtocol.java:563)
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at org.mariadb.jdbc.internal.mysql.MySQLProtocol.close(MySQLProtocol.java:589)
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at org.mariadb.jdbc.MySQLConnection.close(MySQLConnection.java:257)
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at NonFinishedFetch.main(NonFinishedFetch.java:27)
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Locked ownable synchronizers:
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- None
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"VM Thread" prio=10 tid=0x00000000019d5000 nid=0x2073 runnable
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"GC task thread#0 (ParallelGC)" prio=10 tid=0x000000000197c800 nid=0x2071 runnable
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"GC task thread#1 (ParallelGC)" prio=10 tid=0x000000000197e000 nid=0x2072 runnable
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"VM Periodic Task Thread" prio=10 tid=0x0000000001a0e000 nid=0x207a waiting on condition
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JNI global references: 885
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revision-id: wlad@montyprogram.com-20130213220529-3nt9agupszq2cufk
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revno: 409
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branch-nick: mariadb-java-client
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